SUMMARY ? CORE B: METABOLOMICS The development of cancer is inherently linked to alterations in cellular metabolism. Exploration of these changes and the underlying regulatory mechanisms, with the goal of enabling new approaches for the diagnosis and treatment of melanoma, is a long-range objective of this P01 Program Project. The primary overall objective for Core B is to apply metabolic profiling methodology developed by core members for the comprehensive assessment of changes in metabolism upon altered ER homeostasis and mitochondrial function in melanoma, all processes that are tightly linked to central metabolism. Core B will fulfill this objective by a unique combination of methodology to comprehensively analyze metabolism, expertise in interpreting analytical results to explain the broader metabolic picture, and requisite experience in enzymology for detailed follow-up studies on metabolic enzymes. Central metabolism was already a focus for study in melanoma by the investigators of this grant in collaboration with the Core B leaders in the first phase of this P01 program. The Specific Aims of this core are as follows: (1) to provide comprehensive metabolic analytical support to all three collaborating research projects; (2) to characterize the central metabolism of the set of cell lines used in all research projects and Core C (melanoma screening and stratification core); and (3) to provide support to the research projects by assisting in the characterization of enzymes and enzymatic activities. The central method to be used is gas chromatography-mass spectrometry (GC-MS) analysis of polar and apolar metabolites in fractions of cells or medium derived from cultures labeled with stable isotopes (13C). This GC-MS technique yields data on metabolite quantities and also using isotope tracing, on metabolite origins and flux through metabolic pathways. Complemented with other methods to measure substrate uptake (YSI) and for oxygen consumption (Seahorse), it provides a comprehensive assessment of central metabolism. In general, further advances to this novel approach to metabolic analysis will also provide a model for future studies on cancer metabolism and cellular metabolism in general.